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73-87 Chevy _ GMC Trucks => Performance => Topic started by: Lit549 on March 03, 2014, 12:21:11 pm

Title: 6 in rods in a 355 opinions
Post by: Lit549 on March 03, 2014, 12:21:11 pm

I need advice,im building a 355 with scat crank and flat top pistons for my 85 c10 daily driver.Ive read and searched till im blue in the face and still haven't decided if a 6in rod is a good choice for a daily driver? Ive heard the pin is closer to the rings so oil useage and piston rock may be an issue? Ive also read the 6 in rod is a lot easier on skirt pressure and is more efficient? Any suggestions or opinions or maybe experience  in having used a 6 in rod?Again,its a 85 c10 and will have vortech heads w lt4 hotcam and 3.08 gear..About 10-1 compression..thanks in advance

Title: Re: 6 in rods in a 355 opinions
Post by: bd on March 03, 2014, 02:23:42 pm

I run 6" H-beam rods with a Scat forged one-piece crank twisted by forged +0.030" Wiseco flat tops in my 87 355.  There is a slight torque advantage coupled with a slight decrease in piston side thrust - essentially, less energy is wasted and more energy is transferred directly to the crank.  The engine consumes ~1 quart in 3,000 miles, which may be related more to short trip driving.  You may need to relieve the base of the cylinders for adequate rod clearance.  Although I'm a proponent of 6" rods, in reality, benefits likely will go unnoticed in a DD.

My only regret is that I didn't clearance the block for a 3.75" stroker and groove the leading sides of the lifter bores for enhanced lobe oiling while I had it apart.

Title: Re: 6 in rods in a 355 opinions
Post by: Lit549 on March 03, 2014, 11:17:53 pm

What exactly are you talking about with the better oilng to lifters? Never heard of that,i may try that! Thanks

Title: Re: 6 in rods in a 355 opinions
Post by: bd on March 03, 2014, 11:41:04 pm

COMP Lifter Bore Grooving Tool (http://www.summitracing.com/parts/cca-5003/overview/)

Instructions are posted with the tool listing.  It grooves the lifter bore up to the height of the lifter oil relief, so there is a constant supply of oil onto the leading edge of the lifter where it meets the cam lobe.  An alternative is to use laser drilled lifters.  Best time for the procedure is when the block is stripped, before hot tanking.

Title: Re: 6 in rods in a 355 opinions
Post by: Captkaos on March 04, 2014, 12:43:22 pm

For a daily driver, I don't think it would be worth the added cost.

Title: Re: 6 in rods in a 355 opinions
Post by: Lit549 on March 05, 2014, 09:23:32 pm

thanks,ive decided on 5.7 rods and concetrate on heads and cam..And upgrading to forged pistons..Looking @comp extreme energy roller cam setup..